There are several advantageous features of heat pump systems which are not fully exploited. From a residential or small commercial building owners' perspective, there are the obvious savings associated with the installation of any type of heat pump system, as opposed to a conventional electric or fossil fuel system. For the respective utility, there is the potential for reduction in peak demand, and improved load dispersal, over the calendar year. Finally, in a society that has become increasingly conscious of the environment, heat pump systems offer an environmentally sound alternative to building heating and cooling.
In order to introduce a heat pump system using air as the heat source in cold regions, a number of technical problems must be solved, such as degraded performance at outside air temperatures below -8.degree. C., as well as frosting on the evaporator coil at cold outside temperatures. Most of the deficiencies associated with air/air heat pumps have been overcome in our proposed integrated design of heat pump.
The integrated heat pump system combines the proven efficiencies of heat pump technologies with the heat regenerative technologies to give the most efficient heating/cooling system, with capabilities to produce domestic hot water. The system uses environmentally sound blends of refrigerants that have less environmental impact than CFCs, and meet the standards set by the United Nations Environmental Program (UNEP) for Greenhouse Depletion Potential (GDP) and Ozone Depletion Potential (ODP).
The new system is much more efficient than existing air/air split systems for several reasons. In the existing systems, the air heats the refrigerants circulating in the outdoor section of the heat pump, which pass into the indoor system to finally heat the house. Unlike the existing systems, the new system provides a fully integrated unit; the cold air from outside is brought to the unit which is placed indoors. The heat extracted from the cold air is then pumped to heat the house. This reduces the heat loss and refrigerant pipes between the indoor and outdoor sections. Furthermore, the new system utilizes a passive heat pump to preheat the evaporator cold air, which enhances system efficiency in cold weather by reducing frosting on the evaporator. In addition, the refrigerant blend used in the new system is especially formulated to extract more heat from the cold air at lower temperatures.
Since the system uses air as the heat sink, no other cost is involved except air ducting. Therefore, unlike water or ground source heat pumps, it is the most affordable heating and cooling system.
This system is intended for retrofitting houses with fossil fuel furnaces, or for replacing base board electric heating systems.
Prior work has been reported on similar systems, by Dinh, (1), Sami, (2), Linton, J. W. (3 and 4), focused on ventilation and air exchanging of the buildings for humidity and odor control. However, the new system is fully intended for cooling and heating the interior air of the building, rather than providing air exchange or ventilation for buildings.